SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11912cbcc48ff961297655a2ed34f33fd5243d0e3c71822091c9681d59d9e85c' 
  AND token = 'kjdUvWvX+igR+rjtJVll3/4SBz/vzUGytVGAkh4uchc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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