SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '099e38aa2dedd37e0e0f9de9bf351ec9eee965aab5516c39313b85da1c532d75' 
  AND token = 'kmpK0t3sXOMB1SxZKV58509kU8TEcA4+dYGxfG3jZ0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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