SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64aca0bb7847796457e84cffaac941af00126c995cbf75bfe0ffe5f880a60dea' 
  AND token = 'c0giFxM2rBfkBfMkhPUcUvco3VlhmWThPbNRMVJVu6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}