SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c6514440259e78b50bdc68d673eeaf3ef5dbb79045c579f0146d27c73853ed9b' 
  AND token = '++QTKBBsIFfccRYj6zzK2WQcPywZxOg0f6IgBM1FAgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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