SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '975b25b98fd99869cff4c3f9d4a628defac98350643c9d4e1662ed54718cbe48' 
  AND token = 'e+USsQwFXUj+gOf5mSS8U2LVQNNFsmSmFMdrwphRNrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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