SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '517395ee8f6cff09fc4169ab2b0b2a245b62e74b3c1d6fe1912f35774633419c' 
  AND token = 'fvt+Ip0/gx35jt/qFi7yetTNx3uNxxwvTzKXg6LnI8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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