SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53c1caa43d4e418c91ed941cc0a29b42713e10401e9b605aea7590d58eeb63b2' 
  AND token = 'j2LE8zborMNemVfvpIyu0BwZUoVBizNcxbwpdpnDYig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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