SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a03b027d7ccea6421fee7d7379f15b51a92a26f00815e5f0c0d932039dbe29b' 
  AND token = 'L+kXEbuVfQITLd0+7kOAsKLDSX5bG2VWEMZwqyq0imc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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