SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cc0762ada89218b9d987508b2c1f11b3463537f9331f972294fd6225f16bbee' 
  AND token = 'TEnNvb8JFpNclHqEltd/Pbw7sWMqVoE9eG8tHAvEogA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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