SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '742bbd06934361e56dc808ee8284c7b51ccd7d60fdc139ec496f3b47d502b1e3' 
  AND token = 'cCafQb89BqrUQnegDgGf8AhyB+/vT13BoC2xWEsIogw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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