SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a03e8457997105590250b6d3c2ec33347114f3886edaff03ff22c16d7cd843d4' 
  AND token = 'IbLZgiClJe2nkdEtkfqDd3486TeTyIqz8VFLBGZ6CX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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