SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cefe860db21e9a12d613a0f146b7a5c1ff6b2f7959793a0b0cb1bacc22386760' 
  AND token = 'BoU9t8ZXjX+KEoQ737NvGzHCtdwMBGXtGLlxi27TKmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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