SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55c67f13376d4f137beb2c1ba4e106cffcfd9c5f080f5274006d5e0de90369a4' 
  AND token = 'dJPY9zoYCIjLrn7ticK4pqRiLArMoShbxntB4QYfo60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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