SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c3ee276385170f9f2c19402ca657e0dc02d4f8b1bff088405c00632b12c4f8b' 
  AND token = 'FBv78OjTwPEW315vjZKgic9Gpsdl7znGJmo+5+42Sb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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