SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b18b94d07e1dae04783ec8e44c6d1ee64e462c31bda76c6ad517b2bbdb7326c9' 
  AND token = 'hkykbZabLTRKDw44ztw3BEslsc+S0IU/uPbtx4xTWxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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