SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0ad6872b3a7fa1cac9bbdd273e2208186ec96a5e254e248586ed17b5779cfafd' 
  AND token = '9dWvys83A2twZjXcxPrGtCdm2zzq/+4sSD/efeXzqN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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