SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02618a68e5c33f85a62da43e408ee1c49c74cd9994b71c4895a6bbad316d54a0' 
  AND token = 'q8Lhw4VWsMDC441IXLYJwh53qAo0ChgsbMSKaFH3PSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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