SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bf53a91c51b07b86da7938f34b2e2a1c3cd128e8413240e9f5be0bc9e7f7be0' 
  AND token = '4n6S+cNVgtrqQjeoqFd+8ufbGB4c0utddwMMLC2K1mU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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