SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b8c727fb9b062cd400955f2ee86cffe7fec4094291f06a3d791dcd98560ad88' 
  AND token = 'f+mMFydXJ7i0cy8BEUh1hzVwK26zs/Gw7CGFRezhNmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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