SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe171108e479bcdaaa3a05d2e98fdebc5523c75520671adf54e6294f4a1a3c59' 
  AND token = 'dFbadMRG0PHBJReUY/10ch+TLptCSX9SionqA38kG9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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