SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f86a82ff1c4fd6df4d31a5ea499b3f57b22e562db99a302d5236880b108b75e8' 
  AND token = '1U9rhwZiPMigKZHpH856oGomOP/hbZrZBthxkIoHwVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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