SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9215de3c36eba09ed4d14cb17e0917f0b9e5d684ca0f9b4b73c355f6e6830d82' 
  AND token = 'mulUhbPjrZ6SwgsF0PnZm0dc6EMcp6zDglpQ3GveslM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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