SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c66a9801331f188b9dc3c846da818c5231498505c09add5f56407a9793a466fd' 
  AND token = 'sD1p0XZMuamjYmR5zmFdqIehzT5Wh4b/FoBBEZNyAb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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