SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83633bb79df5f0becce2eeff35e5389d7ccdeb43c1288bc182d169c46e306069' 
  AND token = 'ZmaManRQl/Ay0ShvxB3IxaKZHyQlZwcdBYgYhtatPJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}