SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '04f3b12a0d680a2834454a1941cf193858fc2f99f354a1a58edd8432308d0142' 
  AND token = 'GU5fkVsNqduQD/tzRjjhB0Y/8sAopofoh7XmclzK2xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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