SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b42cdd1e7a7d6476f475699352291e89949dc2b7bea6a891d9157c05f3f7a5e6' 
  AND token = 'ergVN+aMTZB1/2zaV9pDX3Jf3p3efYnH506ejbvHLjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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