SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a52fbaf9a5f6a6ce86056e99107e2de2bb2fdc693e8a1814ca837382c9a551ad' 
  AND token = 'q1ymGNiF4BLyLJxwvFIjp/9xE4BU1S38HWxFtt9Ereg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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