SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9bd4abf0b96192b4e870b5e84846ff94417231ad4f89cffac911fb4522a7381' 
  AND token = 'fU0xNMfcCepMImaoySphzqUZTT8tsNwR725Xg0Lq8ww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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