SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce1ad244c5dbca7ee2a0faec13395af5c38385f47af4c4b42653206631d136bb' 
  AND token = 'TmbIlNYQxSzcF7TqlNcxNuu/aqf+1agBpQzjwZXHFwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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