SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3d49d06b280879e75e091df5fb582297b0d0aeadd8b0238e33329ee19eaa6e4' 
  AND token = 'aSaxQOGWfU8O7Ecn5pA8ZwBnLDA0CC/PR4HkwYWI4bQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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