SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52dd9f2578af7ac73956cb77fbbdaade61d72106b4dd31685ba66b118eaf4812' 
  AND token = 'L8GbimECcfna/kvOpzis4apCI2cDLZV/DM2sqLj3N7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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