SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c164050bc0025360cfa9e86c894fddffaac486efc35223833e79aa43e55f53' 
  AND token = 'pmWwnVgKBhjlMf2FZKF5+8ImDNQo19bJwiFjdafkmwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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