SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c8e7a5619b10b21fa89677b75656738d06cea9f45673293f03f2d7de9c916a5' 
  AND token = 'OSe0jIwXWBIYnMRuTSPgVrLxmFVvJyT2YPddpFFylt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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