SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b225ccd116f06131449f6014afb447d4c17a7b61b9cdbe5747f3e66ad643a78' 
  AND token = '7ZTtx7oXojUBE5RPcfQ/TVPCtUzWzJlzwJOW+nXchvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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