SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42cfe4b428463fd2879824599eb461e85802b0110052ef7b05ab9444d73c6ca6' 
  AND token = '8y0UzrringBwo4y0mvljuTm+avQvLVhYM0XqQBcRvWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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