SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '12f1a6086aa409cf157061a8334f3deffd65f1919f4af7e6383304e35a8783be' 
  AND token = 'j1/cyfvImCNqZJkO/b15/SuMYHDGgtF/xOjBwtw9Gk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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