SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f78773f9458ad4a130da073cecc21515f94d6f5f7709c932c4697d07713efca4' 
  AND token = 'FpLUVE5FOc94vniWq5aNM7QaQCABnfRgfA8FULgDOLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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