SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c34b4696bc1f6fb4a82332094d81adf8f36ea3134c5d92aff541b8fb478095c' 
  AND token = 'CgtYN8LxOKzguIqbxIMx2+xsq7Zsh32ZGQaSMslTggY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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