SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6356dce39264a264084a03df89107f0bb5bc46c20e2a7d5481c4da7db52e3abe' 
  AND token = '383ELqFDGQCKbx2r2DBfcAJ4vJ+PDz6wMHRDgN8igIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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