SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '737052857d437a3a2a85def1af8b4d260823f2b5c903513c1a962829fae1e2d0' 
  AND token = 'kzqdhLt800zXK40z9ZnPHO1aEbgtVslPuZm1lUzgE/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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