SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a5f41428c9df1424698806c92bf2b541dde26fdaf477d2b044405fc83a94a8e' 
  AND token = 'hYLtCs7vWiJBiebxkm8NAYtoBQtyPUEhwXyuu9VkATg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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