SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '290969da97467f31758c23cee70735ba887ec50c16b5e5f536f394823d57dfc5' 
  AND token = 'UrvNZfbDmZtH2h4j5r7MYN84DQnuW8gSRevbVutwpdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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