SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8c2855f39a49383cd6b73bfbefa413d45655047945d9e51e7f7fd5cc9f7f362' 
  AND token = 'dWaB2nALtrMg4TqYWGW+l2APxwGJbQ0PvSS/gUAnXRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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