SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b6603dbeedc9ff74387e2ea49cabbc3534c758d59da38df4fe6b4559297773e' 
  AND token = '0mj+laNQWm4MOqGhKZSU0w6LDhfCwPcYwBG2Aou14rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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