SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '521cd837b2599f2f46c96c48955c28f2bc6c4b78bf667ede45233e876f645128' 
  AND token = 'ygk1ploNtm+Y38yaF6ap7I1Cq2r/qRwGlwieltl4g7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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