SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5440057b2afd860a1ed5be452a1ecb9d016cb7d7698b92823127e0c3fd6d7f1' 
  AND token = 'BnCqbOGe+7zCsjoR52HO1s/Zg35+GrZXnjjREjDwvyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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