SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15f43afc6555e297a149a4d4c0ed91f7485978e73fb43c8530f9a5636d7daf74' 
  AND token = 'mYYZrHofZcrKoArTMuzVpoEv4J/y7wjiGDYN6Grx4dg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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