SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b5489d57a570050d6792eab1beca7906b18e37b13363952cd2ffdfbc1b0c2fbe' 
  AND token = '/FKTn0dB+ZTKFxCsAATjBdpctPHHQM0gkYslxv5Y118=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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