SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '600d30235b84b0d4953325ea3bde946ad0155c094e746592b4d4fab8ba17bc9e' 
  AND token = 'RttORtmOXD+vPYvuSgrMGsucsjzOvyes6+peVHoOEfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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