SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03b6c84772c55a4961d556ef2d18bd0da1b2f953f3fbefbb4a2fc3a22fa08b41' 
  AND token = 'NKh8/9zuvodjSPKi5iXeKoVHv+9Pk9YH5QOMALhVY88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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