SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3b48294e2b921a05646d3f6c28e164398f36c78559a69f3a5d72b352f4e23031' 
  AND token = 'q+wrBFCt2efPrYf7N3SsYFjuilCjo+TtK/rwGAsomBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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