SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a427ef9e785818c97e5a64460a826e2a3e6d71aff134e1664d460cacfe36f5e' 
  AND token = 'Z17j3rTHM+7tEG4EYFZ5ieMXkbEoqI4pv+6pNwISAbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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