SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11f4293bee56ea433075f5b602636617418b65dced919086b9b1f2e4dde7a424' 
  AND token = 'NX2oQYhsz71t5LrIOjs/tDr3As4cOxn1SC8FJQrBbco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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