SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34b5fb3fa99089cba5065589f914115c4d37ab9dc556805f7b53f2be729221d9' 
  AND token = 'PEbjAUGC6ZCzXFelYTXHCjT0zWOK+w5khA5NtAZ+fh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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