SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fddb4dc86f27b2f551cb379b749f795011fd4c0ed423220aaa769e99eaaf713c' 
  AND token = 'TmhR2DBgMNcaGDxMpo7JhPUoT9PzJUBmKGhA0DEf2T0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}