SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b3d29cf7b67bac284f2ab297321053d36421c8a3c8dcbfd63df8d16fdf127e4' 
  AND token = 'EmFVOfW0eCmXpaD8yfZ7ge6sR8ICxuyMt8uG1Ly35vU=' 
  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"
    }
  }
}