SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3fc9895abd11c6c483f17d2a2de7d979936213534a1f7f75b34d34730eeb85a' 
  AND token = 'zzh2r5Aeja+rSBhCGifTQ6hTvwFkg/zQ6g39W+A0yLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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