SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d7a254b6c174c6947bb3865534b7241c5cfb31fb16012d63e3e180eddf851b6' 
  AND token = 'XjHI1KbPwhDi67f8w5kUNUxnjkb96+L6yEnmfdbDKjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}