SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33787d0cf25e037f59733bbcecb865bbb62dc867bad53cdccd0fe977c0f4e645' 
  AND token = '0gjVPzShz6SjAqkseSPHPhJvZytL/uTTEGtYMfn/KWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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