SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '00309d14ec1c1b32d0443f109a36ff8e6bb970ab3031bf92f3555a62a38d6183' 
  AND token = '/DcGDojE7N3ZihaFtCqjXVM7QE6ZHNvwFUANSVaw/XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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