SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f864d0021daf76c81029b8df6178ece2824894a279753bd32a78e734a5e1b00b' 
  AND token = 'V3w8m6LsiIX5UbvSPERTidw0jB6okZnnerAV4wbGOiM=' 
  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"
    }
  }
}