SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f57dbe27d5fea7eaa5b80620a9957c419b55536e12d1eee7b455ec5988943b8a' 
  AND token = 'n3Kzh8AoEzAbIKTdk2GOSkiSJkLVPOVepnwKF+OrK1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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