SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c0979381ed7f6f722febe0292e045cc0d9fed6216be765405c88eebfbaf5eb8' 
  AND token = '+Lqn+cWPmAhYDNUKS1usrpJVXz/i7q7sHxqw+NLkYwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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