SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '765818e75e6d09f48f63db874657779401a0bf5cd056d3d940d07f5d8f4c390d' 
  AND token = 'l7U6y71IFHQ32yOqJwB+oYDNGzK/2C2grJ7+2jGet/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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