SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8373b67412dafc5203f359ecd2d7428fe6a100375bee8d1d67e31dcf39969b61' 
  AND token = 'CcNDIqgcuBfukCySkM/kCkx+zjWYGdIfHHyglUbhJPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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