SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb5db3894e12660263db3604ea0a56e319315cf774930b10497fb55a4559882d' 
  AND token = 'ZdY1GGCBvBlN9UvntKCOkhDYU5i2JUB0POgmCNGciqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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