SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9392bd1e8c47df6754c4e56ba2f52c0e9c4418258f401dca5e5f23b6951576a0' 
  AND token = 'zuGLlWeFXrpHu+D/Bw1xRu7O3r4TPqzYI/TnkD+AkCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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