SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f780af5c8d55505140d431eac9faf2f716365290da1874d2947eec7383730edb' 
  AND token = 'zluHKE0AeytvryZvMqzaCZYrScBvwfZUoa98IyTqhEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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